Production of Tagatose by Whole-cell Bioconversion from Fructose Using Corynebacterium glutamicum

• Published in: Biotechnology and bioprocess engineering Vol. 28; no. 3; pp. 419 - 427
• Main Authors: Jeon, Eun Jung, Lee, Young-Mi, Choi, Eun Jung, Kim, Seong-Bo, Jeong, Ki Jun
• Format: Journal Article
• Language: English
• Published: Seoul The Korean Society for Biotechnology and Bioengineering 01.06.2023; Springer Nature B.V; 한국생물공학회
• Subjects: Antisense RNA; Biocatalysts; Bioconversion; Bioengineering; Biotechnology; biotransformation; Calories; Chemistry; Chemistry and Materials Science; Cloning; Copy number; Corynebacterium glutamicum; E coli; Enzymes; Epimerase; Flow cytometry; Fructose; Fruits; Gene expression; Genetic engineering; High-throughput screening; Industrial and Production Engineering; Kosmotoga; Lactose; Optimization; Plasmids; Research centers; Research Paper; Sucrose; Sweetness; Synthetic biology; tagatose; Thermotoga neapolitana; 생물공학; tagatose; fructose; high copy plasmids; whole-cell biocatalyst
• ISSN: 1226-8372; 1976-3816
• DOI: 10.1007/s12257-022-0304-5

s Tagatose is a rarely occurring sugar found in food and sweet fruits. It is a potential sweetener with low calories but a sweetness similar to that of sucrose. In this study, we developed a whole-cell biocatalyst using Corynebacterium glutamicum for direct bioconversion of fructose to tagatose. First, we constructed a biological conversion pathway for the conversion of fructose to tagatose by expressing tagatose 4-epimerase (TN) from Thermotoga neapolitana in C. glutamicum. Next, to increase the expression level of the enzyme, we engineered copy number of plasmid. Plasmid library was constructed by randomizing the cgrI antisense RNA region in the plasmid, and the plasmid with high-copy number was isolated using fluorescence-activated single cell sorting (FACS)-based high-throughput screening. The isolated plasmid, pHCP7, had 2-fold higher copy numbers than the original plasmid. A higher expression level and conversion yield could be achieved using pHCP7. Finally, we examined a novel tagatose 4-epimerase TN(KNF4E) isolated from Kosmotoga olearia. The gene expression level was further increased (33.9% of total fraction) through codon optimization and expression in pHCP7, and a conversion yield as high as 21.7% was achieved.